scholarly journals Genotypic Diversity and Host-Specificity of Frankia Bacteria Associated with Sympatric Populations of Alnus rubra and Alnus rhombifolia in Oregon

2020 ◽  
Vol 93 (3-4) ◽  
pp. 244
Author(s):  
Mehmet A. Balkan ◽  
Nathan U. Stewart ◽  
Emily S. Kauffman ◽  
Emily R. Wolfe ◽  
Daniel J. Ballhorn
Keyword(s):  
Host Specificity ◽  
Genotypic Diversity ◽  
Alnus Rubra ◽  
Sympatric Populations

scholarly journals Reciprocal hybridization between diploid Ficaria calthifolia and tetraploid Ficaria verna subsp. verna: evidence from experimental crossing, genome size and molecular markers

2019 ◽  
Vol 189 (3) ◽  
pp. 293-310 ◽  
Author(s):  
Ondřej Popelka ◽  
Michal Sochor ◽  
Martin Duchoslav
Keyword(s):  
Genome Size ◽  
Morphological Variability ◽  
Plastid Dna ◽  
Genotypic Diversity ◽  
Hybrid Origin ◽  
Aflp Analysis ◽  
Sympatric Populations ◽  
Aflp Data ◽  
Evolutionary Forces ◽  
Genetic Clusters

Abstract Ficaria is a taxonomically intriguing polyploid complex with high morphological variability. Both hybridization and polyploidization have been suggested as the main evolutionary forces behind the high morphological variability in this genus; however, detailed studies are lacking. In Central Europe, two Ficaria taxa (diploid F. calthifolia and tetraploid F. verna subsp. verna) occasionally co-occur in local sympatry, which might result in hybridization. We investigated sympatric populations of the two Ficaria taxa using flow cytometry, chromosome counts, AFLP analysis and plastid DNA sequencing; we also performed experimental homoploid and heteroploid crosses to determine the frequency and direction of hybrid triploid formation, an alternative route of triploid origin (autopolyploidy) and the possibility of a one-step neoallotetraploid origin. Sympatric populations were composed of three genetic clusters corresponding to diploid F. calthifolia (2n = 16), tetraploid F. verna subsp. verna (2n = 32) and triploid plants (2n = 24). The holoploid genome size and AFLP data suggest a hybrid origin of the triploids, thereby making their formation via autopolyploidization in F. calthifolia unlikely. The triploid populations are monoclonal and of independent origin. In contrast, the parental populations exhibit high genotypic diversity and frequent sexual reproduction, including those of predominantly asexual F. verna subsp. verna. Experimental crossing confirmed that both parental taxa produce fertile seeds via a sexual pathway, but not by apomixis, and that both serve as pollen acceptors in heteroploid crosses, which is consistent with the plastid sequencing. However, hybridization is asymmetric, with maternal-excess crosses being significantly more successful. No signs of neoautotetraploidization or neoallotetraploidization were detected. In summary, recent gene flow between the studied Ficaria taxa is either limited or absent.

scholarly journals Relationships of Epichloe typhina isolates from different host grasses

2007 ◽  
Vol 13 ◽  
pp. 451-455
Author(s):  
C.L. Schardl ◽  
A. Leuchtmann ◽  
B.A. Mcdonald
Keyword(s):  
Host Specificity ◽  
Molecular Phylogenetics ◽  
Dactylis Glomerata ◽  
Grass Species ◽  
Sequence Variants ◽  
Geographic Isolation ◽  
Holcus Lanatus ◽  
Isolated Populations ◽  
Sympatric Populations ◽  
Beta Tubulin Gene

Epichloë typhina comprises interfertile strains associated with several grass species in tribes Poeae, Aveneae and Brachypodieae. Molecular phylogenetics indicate that E. typhina is paraphyletic to E. sylvatica and E. clarkii. Although interfertility barriers are evident between E. typhina and E. sylvatica, E. clarkii is interfertile with E. typhina. However, E. clarkii is associated specifically with Holcus lanatus (Aveneae). We addressed the possibility that E. typhina is a complex of genetically isolated populations distinguishable by host specificity. Populations of E. typhina were sampled from three Cantons on a transect from southwest to northeast Switzerland, and from 1-3 host species in each Canton. No fewer than 20 isolates were obtained from each host at each location. The intron-rich 5'-end of the beta-tubulin gene was sequenced from each isolate, and all of the sequences were aligned for phylogenetic and coalescence analyses. There was no indication of geographic isolation of the populations, but no haplotypes (sequence variants) were shared between isolates from different hosts. Therefore, E. typhina appears to be a complex of genetically isolated sympatric populations that are specific for different hosts. Keywords: Brachypodium species, Clavicipitaceae, Dactylis glomerata, Epichloë, epichloë endophytes, grasses, host specificity, molecular phylogenetics, Poa species, Poaceae, population genetics

Alteration of host specificity in Bacillus subtilis.

1968 ◽  
Vol 32 (4_Pt_1) ◽  
pp. 297-301 ◽  
Author(s):  
D D Gwinn ◽  
W D Lawton
Keyword(s):  
Bacillus Subtilis ◽  
Host Specificity
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